Light modules equipped with semiconductor light sources, i.e. LEDs, can now fulfill primary light functions therewith, such that the semiconductor light sources must be cooled accordingly. For this, heat sinks are frequently used, and when semiconductor light sources, e.g. one or more LEDs, are accommodated on a mounting plate, then this mounting plate can then be disposed on a heat sink. The heat sink usually serves thereby as a base body and mounting body or receiving body, such that the mounting plate is held in place via the heat sink. The semiconductor sources can be accommodated on a receiving side of the mounting plate, and the mounting plate is attached to the heat sink via a cooling side lying opposite the receiving side, such that the semiconductor light sources can be cooled through the mounting plate.
Ventilators are frequently provided in order to increase the cooling power, which ventilators generate an air flow that is blown onto the heat sink, in particular over the cooling side thereof. For this, heat sinks frequently have a planar base side, for accommodating a mounting plate having semiconductor light sources, and a cooling side of the heat sink is located on the side opposite the base side, which is provided with a cooling structure. The mounting plate for accommodating the at least one semiconductor light source lies flat with its entire surface on the base side of the heat sink thereby. The air flow from the ventilator is generated only on the cooling side of the heat sink thereby, such that the mounting plate is not exposed to the air flow of the heat sink.
By way of example, DE 10 2009 033 909 A1 shows a light module for a main lighting function of a headlamp, and a semiconductor light source is accommodated on a heat sink, wherein the heat sink has cooling fins, and a cooling structure is disposed on the cooling side opposite the receiving side of the heat sink, which is subjected to the air flow from the ventilator.
A disadvantage thereby is that this results in very heavy light modules, usually having a large and massive heat sink, and a substantial portion of the weight of the light module is caused by the heat sink. Because of the heavy weight, further difficulties arise concerning the accommodation of a light module in the housing for a headlamp, such that it is desirable to provide a light module, having a high cooling power for cooling the at least one semiconductor light source, which has a lighter weight.
DE 10 2007 043 961 A1 shows a light module for a main lighting function of a headlamp having a semiconductor light source, and the semiconductor light source is disposed on a heat sink, which is located in an air guidance channel. An air flow is generated in the air channel by means of a ventilator, such that the semiconductor light sources can be effectively cooled by means of the heat sink and by the air flow. An embodiment of a light module with a lower weight, however, is also impossible with this embodiment, without taking further measures.
WO 2009/048436 A1 shows another design for a light module, wherein a heat sink is provided and serves as an accommodation for the semiconductor light source, and on which cooling channels are formed on the cooling side of the heat sink, through which an air flow generated with a ventilator is guided in order to cool the semiconductor light sources. The semiconductor light sources are disposed on the heat sink via a mounting plate, wherein no air flow is provided on the side of the heat sink on which the mounting plate is disposed, thus not enabling any convection cooling of the mounting plate itself.